The soul, viewing the infallible truth and faithfulness of God, refuses to rely upon human promises. They neither can cause him to rejoice nor can human threatenings terrify him, for he is aware of human mutability. However, he knows the Lord to be a God of truth who keepeth truth forever. He knows the promises and believes them, being so convinced of their certainty as if they were already fulfilled. He therefore rests in them and has a joyful hope in them.Wilhelmus À Brakel, The Christian’s Reasonable Service
Sin is what you do when your heart is not satisfied with God. No one sins out of duty. We sin because it holds out some promise of happiness. That promise enslaves us until we believe that God is more to be desired than life itself (Psalm 63:3). Which means that the power of sin’s promise is broken by the power of God’s. All that God promises to be for us in Jesus stands over against what sin promises to be for us without him.
Future Grace, 9–10.